Intranasal distribution and clearance of thermoreversible gel in an animal model.

BACKGROUND: Poloxamer 407 (P407) has been investigated for an intranasal drug delivery system. However, there is little known about the distribution and clearance of intranasally applied P407. The purpose of this study was to evaluate the distribution and clearance time of P407 in an animal model.

METHODS: Five male pigs were administered the experimental solution (18% of P407 with 0.01% of fluorescein) and the control solution (normal saline with 0.01% of fluorescein) into their right and left nasal cavity, respectively. For quantitative analysis, endoscopic images of each nasal cavity were taken immediately and at 10, 20, 30, and 60 minutes after intranasal administration.

RESULTS: The experimental group showed a significantly wider distribution of fluorescein than the control group at 10, 20, and 30 minutes. The experimental group also showed a significantly higher mean intensity of fluorescein than the control group at 10, 20, and 30 minutes. The mean intensity in the control group was significantly decreased during 30 minutes but the mean intensity in the experimental group was significantly decreased during 60 minutes.

CONCLUSION: A substantial amount of P407 remained in the nasal cavity for at least 30 minutes post-application.